Oh man I actually have a jar where I keep each and every "floor drug" I find at festivals/clubs. It's like a museum.
~2 years ago I was at a festival and a couple of my friends found a fanny pack that had been basically buried by dust/dirt at one of the stages, they picked it up, dusted it off and found ~50 grams of MDMA in it. This sort of began a relatively short stint of casual MDMA use for them, they stopped, but they were just doing small bumps all the time every weekend. Glad they stopped that.
Around that same time, at the same stage at the festival actually, I found a metal vial with a screw on top, pretty sure it was an earplug case. It was dark and I was high as hell on acid, I tried to unscrew it but it was really tight, but I finally got it open and white powder flew out all over my hands. It surprises the shit out of so I basically flung the thing. Probably 2-3 grams of some sort of white powder, probably K or Coke. I didn't think much of it but my buddies were like whaaat why didn't you keep it, I guess I would have, but I was just not in the mindset to be able to deal with that shit had to volley it lol.
I always like when I find weed, obviously you shouldn't consume anything you find on the ground, but weed is pretty reliable.